Due to high cellular charges, and in particular roaming and international roaming expenses, users typically use low cost or free voice over internet protocol (VoIP) services, such as the commercially available service Skype™, when an alternate Internet connection option is available instead of cellular service which may be more expensive. This behavior is generally typical amongst business travelers in hotel rooms with a laptop PC at their disposal. In this scenario, an Internet service may be provided via a wired or wireless (e.g. WiFi®) connection in a typical manner. This behavior is, of course, not in the best interest of the cellular provider who effectively loses voice traffic revenues to the free VoIP services.
To counter this threat, technology is currently being introduced that enables the cellular provider to offer the user a VoIP type service such that traffic related to this service is handled by the cellular provider as opposed to a third party network. This technology may take the form of a soft mobile phone client provided by the cellular operator. In a typical embodiment, this soft mobile phone client may reside in a universal serial bus (USB) stick/flash memory form factor along with a subscriber identity module (SIM) card.
Typically, the user will insert the USB/SIM device into their laptop computer, thus launching a soft mobile phone client on the laptop or PC. Subsequently, the soft mobile phone client will search for Internet connectivity on the laptop or PC (e.g. via WiFi®, WiMAX, Bluetooth®, or other connection) and enable the voice service via this connection. The value proposition for this type of approach may include the promise (from the operator) of better QoS and access to the same familiar package of services normally enjoyed via cellular service. A well known technology which enables this type of offering is Unlicensed Mobile Access (UMA) technology, or as it is more commonly known, Generic Access Network (GAN) as specified in the Third Generation Partnership Project (3GPP).
The problem with this approach is that quite often a user, particularly a business user, will also have high speed cellular PC card (e.g. ExpressCard based) in their laptop which is also equipped with a SIM card and may contain other duplicated functions such as the Non-Access Stratum (NAS) that may be found in soft mobile phone clients.
It is quite common for carriers to market numerous phone brands and cellular PC cards in various form factors. One popular form factor (in particular for business users) is the PC card (PCMCIA or ExpressCard) form factor. However, UMA/GAN is typically viewed as a mid end feature-phone feature and not one applicable to PC cards, thereby making the cellular PC card incapable of VoIP communications.
It is a goal of cellular carriers to maximize Average Revenue Per User (ARPU), build customer loyalty and minimize churn. This is principally what a service like UMA/GAN provides. It enables the user to access, typically via WiFi®, networks at their convenience and benefit, but at the same time, continue to use the application services of the carrier. The hidden benefits to the carrier in this arrangement, in addition to possible fiscal benefits from the basic UMA/GAN service subscription, include: reduced customer churn through avoidance of the lure of alternative VoIP services such as Skype™, and continued access to the carrier's pool of services normally only available via the cellular service, for which the customer may be paying a premium while they are accessing the Internet via WiFi®.
FIG. 1 is a functional block diagram of a conventional soft mobile phone client in a USB stick form factor 100. This entity includes a soft mobile client 101, a SIM card 103, an external USB interface 105, and an internal interface 107 between the soft mobile phone client 101 and the SIM card 103. In the preferred embodiment, the soft mobile phone client 101 includes VoIP 109, NAS 111 and UMA/GAN client 113 components. It should be noted that this soft mobile phone client in a USB stick form factor 100 includes no radio functionality. It relies on there being Internet connectivity available at the PC or Laptop into which the soft mobile phone client in a USB stick form factor 100 is inserted.
FIG. 2 is a functional block diagram of a conventional wireless cellular PC card 200 based on Third Generation Partnership Project (3GPP) technologies. FIG. 2 shows the basic functional architecture of a typical cellular PC card 200. Minimally, this entity in a preferred embodiment includes NAS 111, Access Stratum (AS) 203 and radio frequency (RF) (e.g. WCDMA) 205 components, as well as possibly a host of other peripheral functions 207. The cellular PC card may also include SIM card 103 functionality although it is possible that the SIM card 103 (for example in the case of the mini-card form factor) is remote, and may be located in the laptop in a location such as under the battery. The cellular PC card 200 may be connected to the PC through one of a variety of interfaces 211. In this preferred embodiment an ExpressCard interface is shown.
Issues arise when desired functionality, such as wireless services and UMA/GAN, are contained in multiple physical devices. First, there is the unattractive overhead of dealing with multiple peripheral devices when one would be preferable. Therefore, it would be beneficial to combine these functions into a single physical entity.